Hydrogen powered aircraft.
A hydrogen fuel cell aircraft capable of carrying passengers completed its maiden flight this week, another step forward in low-emission, zero-emission flight.
ZeroAvia's six-seat Piper M-class aircraft, retrofitted with the device that combines hydrogen and oxygen to generate electricity, undertook a taxi, takeoff, full sample route, and landing Thursday.
ZeroAvia said the trip, described as "flying a hydrogen fuel cell powered airliner", was "a world first". However, there are other examples of hydrogen fuel cell aircraft that can accommodate passengers.
The HY4 aircraft, which can carry four people, made its first official voyage back in 2016 when it flew from Stuttgart Airport in Germany. The HY4 was developed by researchers from the German Aerospace Center together with "industry and research partners".
Thursday's ZeroAvia flight was conducted at the company's research and development facility at Cranfield Airport in England – 50 miles north of London. The airport is owned by Cranfield University.
"While some experimental aircraft have flown using hydrogen fuel cells as a power source, the size of this commercially available aircraft shows that paying passengers could very soon get on a truly zero-emission flight," Val Miftakhov, CEO of ZeroAvia said in a statement.
ZeroAvia runs a program called HyFlyer together with project partners Intelligent Energy and the European Marine Energy Center (EMEC).
EMEC has described HyFlyer, backed by the UK government, as aiming to "decarbonise small, medium-range passenger aircraft by demonstrating powertrain technology to replace traditional piston engines in propeller-driven aircraft".
In the next step of the HyFlyer project, ZeroAvia will work towards a flight between 250 and 300 nautical miles from the Orkney Islands, an archipelago in waters off the north coast of mainland Scotland. The aircraft on this flight will use hydrogen fuel cells. Hopefully this trip will take place before the end of 2020.
The news on ZeroAvia's flight logs was a week in which European aerospace giant Airbus released details of three hydrogen-powered concept aircraft that could enter service by 2035.
Named ZEROe, the designs vary in size and style, but are all emission-free and use hydrogen as their main source of power.
One of the designs offers a radical vision of what airplanes might look like in the years to come. With the concept of the "blended wing body", in which up to 200 passengers can be carried, the wings would "fuse" with the main body of the aircraft.
While the widespread adoption of hydrogen in aircraft is still a long way off, land-based transportation is already using the technology, albeit on a small scale. For example, hydrogen buses have been introduced in the British capital, London.
Elsewhere, European company Alstom has developed the Coradia iLint, a train that uses fuel cell technology to convert oxygen and hydrogen into electricity.
According to the company, it can reach speeds of up to 140 kilometers per hour, is quiet and "only emits steam and water".